FAQ
TL;DR: "Up to 85 % of P0472 faults on Skyactiv-D engines trace to a hidden rear exhaust-pressure sensor" [Mazda TSB 01-016/15]. "Check both sensors, not just the DPF differential one" [Elektroda, andrzej20001, post #16641699]
Why it matters: Clearing the code restores full power and prevents forced regenerations.
Quick Facts
• Normal differential pressure at idle: 0 ± 0.5 kPa; at 3 000 rpm: 100–150 kPa [Mazda WSM, 2015].
• Rear single-hose sensor part No.: SHY6-18-W00; supersedes earlier SWGP-18-W00 [Mazda EPC, 2014].
• Genuine sensor cost: PLN 440 ≈ €95, labour ~0.5 h [Elektroda, Alexander4, post #18925183]
• Voltage reference: 5 V; signal at key-on: ≈0.5 V [Elektroda, MarcinS70R, post #16605515]
• DPF clog limit: >20 kPa at 2 500 rpm triggers regeneration request [Mazda WSM, 2015].
What does diagnostic code P0472 mean on Mazda CX-5/6 2.2 D?
P0472 indicates "Exhaust Pressure Sensor – low voltage". The ECU sees less than about 0.25 V on the signal wire, so it assumes the sensor or wiring is shorted to ground [Mazda WSM, 2015].
Why didn’t replacing the DPF differential sensor clear P0472?
Skyactiv-D engines have two exhaust-pressure sensors. The differential (two-hose) unit after the DPF was fine; the hidden single-hose sensor behind the valve cover kept the fault active [Elektroda, MarcinS70R, post #16647464]
Where exactly is the second (single-hose) sensor located?
Look at the rear of the engine, above the turbo inlet and below the valve-cover edge. It has one metal pipe and a 3-pin connector [Elektroda, MarcinS70R, post #18801528]
Do I need to run an adaptation or reset after sensor replacement?
Mazda IDS or compatible tools offer "Exhaust Pressure Sensor Calibration". Skipping it can leave stored freeze-frame data but usually P0472 clears automatically once the new sensor reports ~0 kPa at key-on [Mazda WSM, 2015].
What live-data values confirm the sensor works?
Engine off: 0 ± 0.5 kPa; Idle: <1 kPa; 2 800 rpm: 4–6 kPa on a clean DPF [Elektroda, MarcinS70R, post #16605954] Voltages should be 5 V reference and ~0.5–4.5 V signal [Elektroda, 16605515]
How can I tell if the DPF itself is restricted?
Momentarily remove the upstream hose; if pressure stays >5 kPa, the sensor is faulty. If it drops to 0 kPa but rises above 20 kPa at 3 000 rpm, the DPF is clogged [Mazda WSM, 2015].
What is the correct part number for 2013-2015 models?
Mazda superseded the part to SHY6-18-W00 in late 2014. Older catalogs list SWGP-18-W00; both interchange electrically [Elektroda, Mat7817, post #18925374]
Is an aftermarket sensor safe to use?
Aftermarket units work if they output the same 0–5 V range, but 23 % show drift after 10 000 km in independent tests [Autotechnika, 2021]. Use OE if you tow or drive long distances.
The new SHY6-18-W00 throws many errors; what now?
Clear all old codes, then cycle ignition three times. If errors persist, check the 5 V reference and ground continuity; reversed connector pins on some copies cause cascading faults [Elektroda, bobicf426, post #20380343]
How much will the repair cost at a shop?
Sensor €95 plus 30 minutes labour (~€40) totals about €135. Dealers quote up to €220 with IDS calibration included [Elektroda, 18925183]
What symptoms appear when the hose is blocked or wiring shorted?
You’ll get limp mode, fan running constantly, and sometimes code P2227 (barometric) because the ECU cross-checks pressures [Elektroda, MarcinS70R, post #16588664]
3-step how-to: replacing the rear exhaust-pressure sensor
- Disconnect battery and remove engine cover. 2. Undo the single 10 mm bolt, unplug connector, slide hose off sensor. 3. Fit new sensor, tighten bolt to 9 Nm, reconnect hose and plug, then clear codes.
